* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  list-style: none;
}

.app {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

.menu-contianer {
  flex-shrink: 0;
  height: 300px;
}
.menu{
  display: flex;
  justify-content: space-around;
  height: 36px;
  background-color: skyblue;
  align-items: center;
}


.menu-item {
  position: relative;
}


.menu-item-sel {
  position: absolute;
  top: 100%;
  left: 0;
}

.tab {
  flex: 2;
}

.active {
  color: red;
}

dl {
  display: flex;
}